Cyanide is used or produced in several industries such as gas production, metal plating, pharmaceuticals, and mining [Botz et al. 2004, Young C. A. 2001]. This extensive use of cyanide has resulted in the generation of billions of cyanide waste gallons, which has increased the cyanide spill risk to the environment at several locations such as those at Baia Mare (Romania), Kumtor (Kyrgyzstan), Omai (Guyana), and Summitville (Colo.) [Deschenes et al. 2004, Chew et al. 1999]. Thus, cyanide must be treated before discharging.
Various treatment procedures such as adsorption, complexation, and oxidation are known for treating cyanides [Botz et al. 2004, Young C. A. 2001, Young et al 2001, Otto et al. 1980, Gurol et al. 1985]. The procedures other than oxidation give highly concentrated products in which toxic cyanides still exist. The most common method for treating cyanide is alkaline chlorination. However, improper chlorination of cyanide leads to evolution of toxic cyanogen chloride (NCCl). Chlorination also gives high total dissolved solids (TDS) in the treated water. However, ferrate [FeO4]2−, as a green chemical oxidant, can address some of the concerns of chlorination in the treatment of cyanides [Chang et al. 1997, O'Brien et al. 1998].
There is a need to remove the cyanide, as pollutant, so that existing limited water resources may be purified and recycled. There is also a serious need to clean up the soil from cyanide. There is a need for establishing an inexpensive and efficient method for removing cyanide.